At present, the display apparatus with Active-matrix Organic Light Emitting diode (AMOLED) is extensively applied in many types of products. The AMOLED display apparatus consists of plenty AMOLED pixels with rows and columns. AMOLED pixels usually construct the pixel unit circuit with Thin-Film Transistors (TFTs) to provide a corresponding current for the Organic Light-Emitting Diode (OLED) device. Take a basic circuit of AMOLED as an example. The basic circuit of AMOLED, as shown in FIG. 1, concretely is a 2T1C circuit including two transistors and one capacitor, wherein the two transistors are a switching transistor (T1 as shown in FIG. 1) and a driving transistor (T2 as shown in FIG. 1) respectively, and the capacitor is a storage capacitor Cst. The driving circuit of OLED is controlled by Diver TFT, having a magnitude of IOLED=k(Vgs−Vth)2, where k is a current amplification coefficient determined by Driver TFT characteristic itself and Vth is a threshold voltage of Driver TFT. Easily drifting of the threshold voltage Vth of Driver TFT cause variation in the OLED driving current with the result that pixels color are not uniform, further having negative effect upon whole display effect of a display.